<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<script src="js/knockout-3.4.0.js" type="text/javascript" charset="utf-8"></script>
</head>
<body>
<div data-bind="style: { color: currentProfit() < 0 ? ‘red‘ : ‘black‘ }">
Profit Information
</div>
<script type="text/javascript">
var viewModel = {
currentProfit: ko.observable(150000)
};
viewModel.currentProfit(-50);
ko.applyBindings(viewModel);
//css 中如果想 font-style 需要这样写 fontStyle
// 对应表：
// http://www.comptechdoc.org/independent/web/cgi/javamanual/javastyle.html
</script>
</body>
</html>
原文：http://www.cnblogs.com/tongchuanxing/p/5654712.html